Cryptology ePrint Archive: BibTeX Citation of Report 2004/255

@misc{cryptoeprint:2004:255,
    author = {Izuru Kitamura and Masanobu Katagi and Tsuyoshi Takagi},
    title = {A Complete Divisor Class Halving Algorithm for Hyperelliptic Curve Cryptosystems of Genus Two},
    howpublished = {Cryptology ePrint Archive, Report 2004/255},
    year = {2004},
    note = {\url{http://eprint.iacr.org/}},
}

You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.